Hello,
So my question is, our body uses a certain amount of energy through the day and 20% of that is used exclusively by the brain.
Why can’t we increase or decrease the calorie usage of our minds to burn more or less calories?
My own theory is that the brain runs on a base threshold of energy and it normally is around 20% but it doesn’t explain why doing brain teasers/puzzles doesn’t increase it.
And bonus if you can explain how doing extremely challenging problems for any amount of time makes you feel physically tired (such as taking a test).
Edit: there have been a amazing amount of answers while I was asleep (posted this before sleeping for a solid 10 hours), my questions about the brain functionality has been answered
In: 7004
First it’s important to know that you DON’T only use 10% of your brain at once. That’s a silly myth.
We know that nearly all of the brain is “in-use” almost all of the time that you’re alive (this is a very rough generalization but for eli5 we won’t go into complicated details)
And remember the brain is not a computer, it’s meat
Your muscles are meat too, but the brain is not a muscle, it’s a different kind of meat. Also remember, you have LOTS more muscle-meat than brain-meat.
Thinking really hard does increase the activity in the brain. But the brain is not like your computer, it doesn’t simply need more electricity to go ‘faster’. Your brain uses special chemicals that allow electrical activity instead. Your body cannot simply ‘burn’ calories to make this ‘faster’ or ‘stronger’, it is a very complicated process.
So all the parts of your brain need to keep working constantly so you can stay alive and healthy. The amount of work each is doing at one time can change but overall it stays pretty consistent. When one part needs rest a different part will pick up the slack. When you think very hard some areas become ‘quieter’ and some become more active. Now to your question: can we measure the changing caloric usage of the brain when that happens?
Well the issue is that the body, the rest of your meat as a whole, is *very* responsive to the brain. So when you are thinking very hard the rest of the body WILL burn *significantly* more calories above the resting metabolic rate.
There is no good way to measure exactly how much of that extra usage is just “for” the brain, lot’s of people try to guess but we don’t really know for certain. But we do know that caloric usage is a lot less (about one fifth) than what is used by the rest of the body.
So we can’t really say that the brain is going to burn a lot more calories when thinking hard because even if you do end up using a lot more calories when thinking very hard those calories are mostly burnt from the effect of thinking on the body, not from the thought itself
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